There are several disadvantages concerning use of a combustion furnace in houses and similar buildings. In order to supply air for combustion, cold air are drawn in from various leaks in the building. Draughts and unequal temperature allocation will thus arise, with high temperatures around the furnace and cold spots at areas where the cold air is drawn in.
From Norwegian patent publication 59825, blowing air around a furnace is known. Simultaneously, it is suggested to suck outdoor air into the room. This heat exchange offers poor control of the air currents, both concerning whereform and whereto. The furnace temperature is reduced as is the corresponding combustion efficiency.
In U.S. Pat. No. 2,610,565 the inner negative pressure in rooms with combustion furnaces, is reduced by sucking in filtered outdoor air. In this way the suction of uncontrolled and unfiltered air gets moderated. However this solution does not remove the disadvantages concerning the unequal temperature allocation in the building and the creation of condensation in cold and damp areas.
In addition to the combustion- and heating problems which hopefully will be improved, there is an unfortunate collection of gasses and evaporation in certain areas, in many houses or the similar with combustion furnaces. Gasses can originate from the foundation or may be secreted from cigarettes, products in the building or from pollution.